Fins for watercraft come in various formats. Fins are typically attached to the watercraft or form a part of the watercraft, usually in a position underneath the watercraft to have constant contact with the water. Fins help keep the watercraft moving in the desired direction. Most surfboards and Standup Paddle (SUP) boards have fins, and most fins break on impact with an external force (e.g., hitting a rock or other hard object during use in the water or during transport). The fin may break or snap off the board upon impact, and the attachment point of the fin to the board may also break.
Repairing a board after a break is costly, and the board is never “good as new” after a fin repair. Water tends to get into the inside portion of the board (that should stay dry), which can cause water damage that can be difficult or even impossible to reverse. A broken fin housing on an inflatable board may be repaired if done professionally, which can be costly.
Attempts to reduce damage to the fins include providing retractable fins, similar to U.S. Pat. No. 5,356,324. A parallel retracting fin is disclosed in U.S. Pat. No. 8,657,639. U.S. Pat. No. 3,516,100 discloses an adjustable fin depth based on speed of the watercraft. U.S. Pat. No. 8,632,373 discloses a side-folding fin. U.S. Pat. No. 9,067,653 discloses a fin for a plastic board, and, while it does describe a retractable fin, the fin and fin housing is specific to a specific vessel, and is made to be fixed in certain set positions. These are not solutions that can be used with various types of watercraft boards.